Species Redistribution Could Trigger Major Changes

Climate change will unbalance ecosystems

Planetark.org

, April 11, 2002

LONDON - Climate change over the next 50 years will throw delicate ecosystems
off balance, reduce the geographical range of many species and bring new
predators and prey together, scientists said yesterday.

Fewer species than expected will become extinct but their distribution could
be radically different in the years to come which will have unpredictable
results for humans.

"This is important because the modifications affecting our climate are like a
big experiment the world is doing without knowing what's going to happen," said
A. Townsend Peterson, of the University of Kansas Natural History Museum and
Biodiversity Research Center.

Townsend and his Kansas colleagues and scientists in Mexico and California
produced a new model of climate change based on an analysis of its impact on
more than 1,800 species of mammals, birds and butterflies in Mexico.

The research, reported in the science journal Nature , could offer new
insights and guidance to conservationists and policy makers.

The scientists used computer simulations to calculate how climate change will
impact on individual species and where they will be likely to survive in the
next half century.

"Deleting a species here and there will produce effects of unknown
properties. We don't know what will happen when you delete five percent of the
species and we were finding as high as 40 percent of species removed at times,"
Townsend said in a telephone interview.

"That is a scary result."

The scientists studied species in Mexico because of its biodiversity. The
most worrying result was the reshuffling of ecological communities - species
that live together.

They predicted the biggest disruption of ecosystems will probably be in the
Chihuahua desert.

Townsend said each species shows an individual response to climate change
which is complicated and that the rearrangement of ecological communities may be
more serious than expected.

"If you remove enough species from an ecosystem, it's like the old child's
game of pick-up sticks - there are only so many changes you can make before the
ecosystem just rearranges, and maybe strikingly," Townsend added.